托福语法满分精要里跑上来有道题目:
The unique ability of the horseshoe crab detected bacterial endotoxins was a
Achance discovery in the 1970's at the Marine Biological Laboratory in Woods-Hole,Massachusetts.
unique 是 A
detected 是 B
a(Achance前)是 C
discovery是 D 答案是B,正确的是to detected
但我觉得c的a是否有问题啊,是用an吧?
各位,能否说一下,不要见怪,多谢了!